- The USGS did not include a very large number (~100) of drainages in northern Nevada containing known Carlin gold deposits when it chemically re-analyzed the 1970-1980s NURE program stream sediment samples at the end of the 20th century. The lack of stream sediment geochemical data from these deposits detracts from the task of mathematically encompassing variation in Carlin type gold deposit characteristics like size, depth of burial, and ore grade when building a geochemical model of this particular deposit class.
- The Carlin type gold deposit primary system geochemistry is relatively complex. This means that a relatively large number of controlling variables is needed to do the best job of statistically estimating a production function for the Carlin type gold ore bodies. When doing such statistical work, the larger number of controlling variables, the larger the needed geochemical index cases (discovered deposits with defined reserves and/or production).
DIR was able to gain access to and sample about 50 additional drainage cells containing Carlin gold deposits with known production and/or gold reserves during this July field work. Geologically, it was striking how each and every surface-exposed deposit visited evidenced large volumes of very strongly carbonaceous siltstone and/or limestone in the mine workings. Curiously, not all that much is said about this consistent Carlin type deposit characteristic in the economic geology literature.
One of the mining districts visited during July was the Jerritt Canyon/Independence Mountains Carlin type gold district of northern Nevada. The picture below the text provided here shows the current density of unreclaimed drill roads and mine workings in the Jerritt mining district. This sort of thing happens when discovered mines are not all that productive and profitable, and when the means of finding them isn't very discriminating. From ground level, the unreclaimed drill road density is also very obvious.
The geochemical data from the July Nevada stream sediment sampling will be used to refine DIR's Carlin type gold deposit production function. The refined function will, in turn, be used to steer DIR's green and brownfields Carlin type gold prospect generation work in Nevada. This prospect generation work should begin by the last week or two of this month.
DIR follow-up sampling of the five greenfields/brownfields gold prospects generated by last year's stream sediment sampling in the Republic area of northeast Washington was abbreviated in late August after about 50% of the follow-up work had been completed. Active forest fires there (temporarily) closed down road and other access to nearly all prospective land there. DIR plans to return to Washington next spring -- while things are still green and wet -- in order to finish the follow-up sampling needed.